30-06 chrono numbers [Archive] - Glock Talk

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GlockJD
11-15-2010, 17:12
Working up my .30-06 loads I ran into some weird numbers through the chrono. I am assuming the second string is bad data, I was having a lot of errors saying it missed the start sensor and only caught the stop sensor for the first couple sets. The ones that read showed almost 500 over all the rest and they were the lightest loads?

String 1 was supposed to be 52.5 gr of IMR4350 but it errored 4 times and 1 time showed 2570 but it got erased from memory. all of my 53gr loads errored and finally got 2 loads to show up at 53.5 and they are the ones that showed up as 3194 and 3098 for String 1. Subsequent strings went up by .5 grains to a max of 57gr. Never quite hit the 2900 fps of the books but the rifle I was using was only 22" barrel. No signs of over pressure and seems like a pretty good consistency once the chrono settled down, I really had to fine tune the angle over and over to get it reading right, a lot more than I have with pistol shooting. How do these numbers look to everyone else?

Total Strings = 8
Feet Per Second

String 1
1) 3194.0 48.0
2) 3098.0 -48.0

High: 3194.0
Low: 3098.0
E.S.: 96.0
Ave.: 3146.0
S.D.: 67.9
95%: 862.7

String 2
1) 2657.0 6.7
2) 2656.0 5.7
3) 2638.0 -12.3

High: 2657.0
Low: 2638.0
E.S.: 19.0
Ave.: 2650.3
S.D.: 10.7
95%: 32.6

String 3
1) 2690.0 -1.8
2) 2702.0 10.2
3) 2690.0 -1.8
4) 2685.0 -6.8

High: 2702.0
Low: 2685.0
E.S.: 17.0
Ave.: 2691.8
S.D.: 7.2
95%: 13.2

String 4
1) 2725.0 0.5
2) 2724.0 -0.5

High: 2725.0
Low: 2724.0
E.S.: 1.0
Ave.: 2724.5
S.D.: 0.7
95%: 8.9

String 5
1) 2735.0 -18.0
2) 2761.0 8.0
3) 2782.0 29.0
4) 2751.0 -2.0
5) 2736.0 -17.0

High: 2782.0
Low: 2735.0
E.S.: 47.0
Ave.: 2753.0
S.D.: 19.5
95%: 27.1

String 6
1) 2763.0 9.8
2) 2735.0 -18.2
3) 2750.0 -3.2
4) 2749.0 -4.2
5) 2769.0 15.8

High: 2769.0
Low: 2735.0
E.S.: 34.0
Ave.: 2753.2
S.D.: 13.3
95%: 18.5

String 7
1) 2765.0 -11.8
2) 2780.0 3.2
3) 2788.0 11.2
4) 2753.0 -23.8
5) 2798.0 21.2

High: 2798.0
Low: 2753.0
E.S.: 45.0
Ave.: 2776.8
S.D.: 18.0
95%: 25.0

String 8
1) 2797.0 0.2
2) 2812.0 15.2
3) 2779.0 -17.8
4) 2788.0 -8.8
5) 2808.0 11.2

High: 2812.0
Low: 2779.0
E.S.: 33.0
Ave.: 2796.8
S.D.: 13.7
95%: 19.0

(End Of Data)

rg1
11-15-2010, 18:08
Velocities look normal for 30-06 150 grain bullets using IMR 4350. The high readings at low powder charges must have been reading the muzzle blast? The other groups look normal and velocity at 57 grains is about what you'd expect to get even in a 22" barrel. You shooting 150's or 165's?

GlockJD
11-15-2010, 18:32
forgot to mention that, 165 gr Hornady SSTs. I was thinking the same with the muzzle blast so I moved the windscreens further out but errors were just as bad, ended up moving them in closer, closer to 10 feet instead of 12 that I started at and it finally settled down. It was a little breezy to start and I wondered about that but it got worse as the day went on and yet got more consistent.

albyihat
11-15-2010, 23:15
I'm a big fan of 4350 and the 165gr SST great accuracy, good expansion, and cheap. I've taken many deer and elk with this combo.